Automated cchd screening and detection

ABSTRACT

Automated critical congenital heart defect (“CCHD”) screening systems and processes are described. A caregiver may be guided to use a single or dual sensor pulse oximeter to obtain pre- and post-ductal blood oxygenation measurements. A delta of the measurements indicates the possible existence or nonexistence of a CCHD. Errors in the measurements are reduced by a configurable measurement confidence threshold based on, for example, a perfusion index. Measurement data may be stored and retrieved from a remote data processing center for repeated screenings.

PRIORITY CLAIM AND RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/195,037, filed Jun. 28, 2016, and titled “AUTOMATED CCHD SCREENINGAND DETECTION”, which application is a divisional of U.S. patentapplication Ser. No. 13/733,782, filed Jan. 3, 2013, and titled“AUTOMATED CCHD SCREENING AND DETECTION”, which application claims apriority benefit under 35 U.S.C. §119 to the following U.S. ProvisionalPatent Applications:

Serial No. Date Title 61/583,143, Jan. 4, SYSTEMS AND METHODS AUTOMATING2012, CCHD SCREENING AND DETECTION, 61/703,132, Sep. 19, SYSTEMS ANDMETHODS AUTOMATING 2012, CCHD SCREENING AND DETECTION.Each of the foregoing disclosures is incorporated by reference herein inits entirety.

FIELD OF THE DISCLOSURE

The present application relates to the field of pulse oximetry.Specifically, the present application relates to the field of infantoxygen saturation monitoring and congenital heart defects screening.

BACKGROUND OF THE DISCLOSURE

Pulse oximetry screening can identify some critical congenital heartdefects (“CCHDs”), which also are known collectively in some instancesas critical congenital heart disease. CCHDs are structural heart defectsthat often are associated with hypoxia among infants during the newbornperiod. Infants with CCHDs are at risk for significant morbidity ormortality. There are several defects that could be considered CCHDs.However, in the context of newborn pulse oximetry screening at the timeof preparation of the present application, the Centers for DiseaseControl and Prevention (“CDC”) for the U.S. government classify seven(7) defects as CCHD: hypoplastic left heart syndrome, pulmonary atresia(with intact septum), tetralogy of Fallot, total anomalous pulmonaryvenous return, transposition of the great arteries, tricuspid atresia,and truncus arteriosus. According to the CDC, these seven CCHDsrepresent about seventeen to about thirty one percent (17-31%) of allcongenital heart disease.

Patent ductus arteriosus (“PDA”) is common in infants with several ormore of the above seven (7) defects. In the developing fetus, the ductusarteriosus (“DA”) 102 shown in FIG. 1 is the vascular connection betweenthe pulmonary artery 106 and the aortic arch 104 that allows most of theblood from the right ventricle 110 to bypass the fetus' fluid-filledcompressed lungs. During fetal development, this shunt protects theright ventricle 110 from pumping against the high resistance in thelungs 108, which can lead to right ventricular failure if the DA 102closes in-utero.

When the newborn takes its first breath, the lungs open and pulmonaryvascular resistance decreases. In normal newborns, the DA issubstantially closed within twelve to twenty four (12-24) hours afterbirth, and is completely sealed after three (3) weeks.

In the case of PDA, high pressure oxygenated blood from the aorta 104leaks or flows back into the pulmonary artery 112 and back to the lungs108 with normal deoxygenated venous blood. The additional fluidreturning to the lungs increases lung pressure to the point that theinfant may have greater difficulty inflating the lungs. This uses morecalories than normal and often interferes with feeding in infancy.Moreover, an open (patent) DA 102 alters the flow in the descendingaorta 118, which, as a result, changes the blood oxygen saturation inthe feet.

Without screening, some newborns with CCHDs might be missed because thesigns of CCHD might not be evident before an infant is discharged fromthe hospital after birth. Other heart defects might be consideredsecondary screening targets. Some of these heart defects can be just assevere as the primary screening targets and also require interventionsoon after birth. These secondary targets include aortic arch atresia orhypoplasia, interrupted aortic arch, coarctation of the aorta,double-outlet right ventricle, Ebstein anomaly, pulmonary stenosis,atrioventricular septal defect, ventricular septal defect, and singleventricle defects (other than hypoplastic left heart syndrome andtricuspid atresia).

Current CDC recommendations focus on screening infants in the well-babynursery and in intermediate care nurseries or other units in whichdischarge from the hospital is common during an infant's first week oflife. At the time of preparation of the present application, the CDCpromulgated a CCHD screening process 200 reproduced as FIG. 2, directedtoward oxygen saturation measurements, or percentages measured using,for example, a standard pulse oximeter.

According to the CDC's CCHD screening process 200 of FIG. 2, a screen isconsidered positive (see box 228) if (1) any oxygen saturationmeasurement is less than ninety percent (<90%) (in the initial screen orin repeat screens) (see boxes 206, 214, and 222); (2) the oxygensaturation measurement is less than ninety five percent (<95%) in theright hand and foot on three measures (see boxes 208, 216, and 224),each separated by one (1) hour (see boxes 204, 212, 220); or (3) agreater than three percent (>3%) absolute difference exists in oxygensaturation measurements between the right hand and foot on threemeasures (see boxes 208, 216, and 224), each separated by one (1) hour.Any screening that is greater than or equal to ninety five percent(≧95%) in the right hand or foot with a less than or equal to threepercent (≦3%) absolute difference in oxygen saturation measurementsbetween the right hand and foot is considered a negative screen andscreening would end (see boxes 210, 218, 226, and 230).

The CDC recommends any infant receiving a positive screen receive adiagnostic echocardiogram, which would involve an echocardiogram withinthe hospital or birthing center, transport to another institution forthe procedure, or use of telemedicine for remote evaluation. This can beexpensive, disruptive, and possibly harmful to the infant. For example,at the time of preparation of the present application, an echocardiogramto verify an out-of-range (positive) screen could cost several hundreddollars.

Thus, false positives are to be avoided. The CDC believes that falsepositives are decreased if the infant is alert, and timing pulseoximetry screening around the time of newborn hearing screening improvesefficiency.

Pulse oximetry screening may not detect all CCHDs, so it is possible fora baby with a negative screening result to still have a CCHD or othercongenital heart defect.

SUMMARY OF THE DISCLOSURE

The CCHD screening process of FIG. 2 incorporates multiple measurementsites, such as, for example, a baseline site of the right hand and asecondary site of the feet or left hand. In some cases, a stereo pulseoximeter, such as the one disclosed in U.S. Pat. No. 6,334,065 (the '065patent), incorporated by reference herein, could use two (2) or more ofits associated sensors, one for each of multiple sites to accomplish themeasurements. In fact, the '065 patent discusses the use of its sensorfor multiple sites to determine indications of PDA, Persistent PulmonaryHypertension in Neonates (“PPHN”), and Aortic Coarctation. However, veryfew if any institutions possess stereo pulse oximeters.

Rather, in most if not all circumstances, the CCHD screening process ofFIG. 2 will be implemented on a single site pulse oximeter. Thecaregiver will apply the sensor to the first site, such as the baselineright hand, and take measurements. The caregiver will then remove thesensor from the first site, and transfer it to the second site, such asa foot, left hand, etc. and take measurements. As shown in FIG. 2, theCCHD screening process relies on the delta (or difference) between thetwo measurements.

Drawbacks may occur using the single sensor implementation. For example,there will be a time differential between the first baseline measurementand the second alternate site measurement when the caregiver changessites. In infants, the parameters measurable with today's oximeters,including but not limited to oxygen saturation (“SpO₂”), vary withinrelatively short periods. This is exacerbated when infants are exited,crying, or otherwise agitated.

In the most straightforward scenario where the SpO₂ measurements aresomewhat varying, the single sensor implementation of CCHD screening maydetermine, for example, an infant's SpO₂ during a valley or trough ofvarying SpO₂ values for the baseline measurement, and quite accidentallyduring a peak of varying SpO₂ values for the alternate measurement. Suchtime displaced measurements could appear anywhere on an infant's SpO₂waveform. Thus, the differential between the baseline measurement andthe alternate measurement, which is the key to determining positive ornegative screenings under the CCHD screening process, could be subjectto error. This is exacerbated as the CCHD screening process may requirethree (3) or more screenings before rendering a conclusion. Thus, ascreening process may include measurements taken under different dataconditions at each screen, and then again across the screens.

To overcome these and other drawbacks, the present disclosure includessystems and methods automating CCHD screening and detection. In anembodiment, a processor executes one or more processing modules toimprove a likelihood that during a single sensor implementation of CCHDscreening, the measurement values while time displaced, correspond todata conditions similar to one another. In addition, the processingmodule may determine the best sites for measurements.

In an embodiment, an oximeter or communicating monitor controls andtracks the implementation of the screening process, includinginstructions to caregivers on next steps. For example, a straightforwardinstruction may include “Attach Sensor to Right Hand,” “Attach Sensor toAlternate Site,” “Attach Sensor to Right Foot,” “Attach Sensor to LeftFoot,” “Calm Patient,” “Adjust Sensor Positioning,” or the like. Theoximeter may also include a quality indicator providing information onthe confidence in the screening measurements. A quality measure may beincluded for each measurement, for the entire screen, or the like. Forexample, the display may indicate “Positive Screen, 72% Confidence.” Inan embodiment, a minimum confidence threshold may be used to instruct acaregiver to repeat the measurements and/or restart the screeningprocess. Moreover, the oximeter may produce an audio/visual alarmindicating time for a repeat screen, may accept patient informationincluding a patient identifier, and the like.

In other embodiments, the oximeter may communicate with a host digitalnetwork or system to store or upload measurement data associated with aunique identifier to a remote processing center. That network or systemmay include multiple networks or systems. However, the oximeter mayaccess previously stored information, such as, for example, earlierscreening data stored at the remote network, to complete or incrementthe CCHD screening process. In an embodiment, a first network may be aninstitutional network such as a hospital data system, a cellular orother data system, or the like, wirelessly communicating with theoximeter or monitor. The system or systems eventually allowcommunication to a remote data server or processing center that storesthe measurement information in a manner that provides for retrieval andappropriate association with newly acquired data.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features thereof have been described herein. Of course, it isto be understood that not necessarily all such aspects, advantages orfeatures will be embodied in any particular embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings and the associated descriptions are provided toillustrate embodiments of the present disclosure and do not limit thescope of the claims.

FIG. 1 illustrates a diagram of a portion of a circulatory systemincluding a heart having a patent or open ductus arteriosus.

FIG. 2 illustrates an embodiment of a CCHD screening process provided bythe CDC.

FIG. 3A illustrates a simplified view of a pulse oximeter configured toperform a CCHD screening process, according to an embodiment of thedisclosure.

FIG. 3B illustrates a simplified block diagram of a pulse oximeterconfigured to perform a CCHD screening process, according to anembodiment of the disclosure.

FIG. 3C illustrates an example CCHD screening process according to anembodiment of the present disclosure.

FIG. 4 illustrates a simplified perspective view and block diagram of apulse oximeter configured to perform a CCHD screen process includingdual sensors, according to an embodiment of present disclosure.

FIG. 5 illustrates a data diagram of a data sharing system, according toan embodiment of present disclosure.

FIG. 6 illustrates an example screen shot of a pulse oximeter monitorconfigured for measuring CCHD, according to an embodiment of the presentdisclosure.

FIG. 7 illustrates an example screen shot, including spot checksettings, of a pulse oximeter monitor configured for measuring CCHD,according to an embodiment of the present disclosure.

FIGS. 8-9 illustrate example screen shots, including test results, of apulse oximeter monitor configured for measuring CCHD, according to anembodiment of the present disclosure.

FIGS. 10A-B illustrate example screen shots, including alternativescreening settings, of a pulse oximeter monitor configured for measuringCCHD, according to an embodiment of the present disclosure.

FIGS. 11A-B illustrate example screen shots, including additionalsettings, of a pulse oximeter monitor configured for measuring CCHD,according to an embodiment of the present disclosure.

FIGS. 12A-C, 13A-C, and 14A-D illustrate example screen shots, includinginstructions for single sensor operation, of a pulse oximeter monitorconfigured for measuring CCHD, according to an embodiment of the presentdisclosure.

FIG. 15 illustrates an example plot of pre- and post-ductal SpO₂measurements in a CCHD screen process, according to an embodiment of thepresent disclosure.

FIG. 16 illustrates an example plot of pre-ductal perfusion index andconfidence measurement in a CCHD screen process, according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure generally relates to systems and methodsautomating critical congenital heart defects (“CCHDs”) screening anddetection. In an embodiment, the CCHD screening process may beimplemented on a single site pulse oximeter. A caregiver will apply thepulse oximeter sensor to the first site, such as the right hand, andtake baseline measurements including, for example, blood oxygensaturation (“SpO₂”). The caregiver will then remove the pulse oximetersensor from the first site, and transfer it to the second site, such as,for example, a foot or left hand, and take measurements. As shown inFIG. 2, and as described above, the CCHD screening process relies on thedelta (or difference) between the two measurements. Then, a processorexecutes one or more processing modules to improve a likelihood thatduring a single sensor implementation of CCHD screening, the measurementvalues, while time displaced, correspond to data conditions similar toone another. In addition, the processing module may determine the bestsites for measurements.

As used herein, the terms pulse oximeter, CCHD screening system, CCHDmeasurement device, and CCHD monitor may be used interchangeably.

FIG. 1 illustrates an infant heart 100 having patent ductus arteriosus(“PDA”), and lungs 108. The infant heart 100 includes a ductusarteriosus 102, an aorta 104, a pulmonary artery 106, a right ventricle110, a main pulmonary artery 112, a left ventricle 114, an innominateartery 116, a descending aorta 118, and a subclavian artery 120. Theductus arteriosus 102 frequently fails to close in premature infants,allowing left-to-right shunting, i.e. oxygenated “red” blood flows fromthe aorta 104 to the now unconstricted pulmonary artery 106 andrecirculates through the lungs 108. A persistent patent results inpulmonary hyperperfusion and an enlarged right ventricle 110, whichleads to a variety of abnormal respiratory, cardiac and genitourinarysymptoms. Current PDA diagnosis involves physical examination, chestx-ray, blood gas analysis, echocardiogram, or a combination of theabove. For example, large PDAs may be associated with a soft, long,low-frequency murmur detectable with a stethoscope. As another example,two-dimensional, color Doppler echocardiography may show a retrogradeflow from the ductus arteriosus 102 into the main pulmonary artery 112.Once a problematic PDA is detected, closure can be effected medicallywith indomethacin or ibuprofen or surgically by ligation. Multiple dosesof indomethacin are commonplace but can still result in patency,demanding ligation. A drawback to current diagnostic techniques is thatclinical symptoms of a PDA can vary on an hourly basis, requiringextended and inherently intermittent testing.

In a single sensor implementation of noninvasive PDA determination orCCHD screen (as described below in referenced to FIGS. 3A-C), a sensor,such as a blood oxygenation sensor, may be placed on the right hand todetermine a baseline of physiological data. For example, a pulseoximetry sensor at the right hand provides physiological data signalsindicative of arterial oxygen saturation and a plethysmograph for bloodcirculating from the left ventricle 114 through the innominate artery116, which supplies the right subclavian artery leading to the rightarm. Because the innominate artery 116 is upstream from the PDA shunt atthe ductus arteriosus 102, the oxygen saturation value andplethysmograph waveform obtained from the right hand are relativelyunaffected by the shunt and serve as a baseline for comparison withreadings from other tissue sites.

A sensor may then be placed on a foot to provide oxygen status for bloodsupplied from the descending aorta 118. The shunt at the ductusarteriosus 102 affects aortic flow. In particular, the shunt allows atransitory left-to-right flow during systole from the high pressureaorta 104 to the low pressure pulmonary artery 106 circulation. Thisleft-to-right flow through the shunt at the ductus arteriosus 102 altersthe flow in the descending aorta 118 and, as a result, affects theoxygen saturation value and plethysmograph waveform measured at thefoot. The PDA condition, therefore, may be manifested as a normalplethysmograph with a characteristically narrow peak and well-defineddicrotic notch at the right-hand baseline site compared with a dampedplethysmograph with a broadened peak and reduced or missing notch at thefoot site. Further, the foot site waveform may be phase shifted from thebaseline waveform. These plethysmograph differences are accompanied bycomparable differences in arterial oxygen saturation values between theright-hand site and the foot site.

As an alternative, the sensor may be placed on the left hand to provideoxygen status for blood circulating from the left ventricle through theleft subclavian artery 120 that supplies the left arm. Because the leftsubclavian artery 120 is nearer the shunt at the ductus arteriosus 102than the further upstream innominate artery 116, it may experience somealteration in flow due to the shunt at the ductus arteriosus 102. ThePDA condition, therefore, may also be manifested as an alteredplethysmograph waveform at a left hand site as compared with the righthand baseline site, although likely to a lesser degree than with a footsite. Thus, the PDA condition, and thus a CCHD condition, can bedetected and its treatment monitored from a delta in saturation (i.e.,difference in SpO₂) values and plethysmograph morphology and phasecomparisons between a right hand baseline sensor site and one or moreother sites, such as the left hand or foot. One of ordinary skill willrecognize that multiple site comparisons using an oximeter may also beused to detect other cardiac abnormalities that cause mixing ofoxygenated and deoxygenated blood, such as a ventricular hole or apatent foramen. Further, abnormal mixing of oxygenated and deoxygenatedblood may also be manifested in physiological data measurements otherthan oxygen saturation provided by an advanced patient monitor or pulseoximeter.

FIG. 3A illustrates a simplified view of a pulse oximeter configured toperform a CCHD screening process with a single sensor (as describedabove), according to an embodiment of the disclosure. FIG. 3A includes apulse oximeter 300, a display 302, and a sensor 304. In an embodiment,the sensor 304 may be noninvasively attached to the patient's finger.The sensor 304 may measure various blood analytes noninvasively usingmulti-stream spectroscopy. In an embodiment, the multi-streamspectroscopy may employ visible, infrared and near infrared wavelengths.The sensor 304 may be capable of noninvasively measuring blood analytesor percentages thereof (e.g., saturation) based on various combinationsof features and components.

The sensor 304 may include photocommunicative components, such as anemitter, a detector, and other components. The emitter may include aplurality of sets of optical sources that, in an embodiment, arearranged together as a point source. The various optical sources mayemit a sequence of optical radiation pulses at different wavelengthstowards a measurement site, such as a patient's finger. Detectors maythen detect optical radiation from the measurement site. The opticalsources and optical radiation detectors may operate at any appropriatewavelength, including infrared, near infrared, visible light, andultraviolet. In addition, the optical sources and optical radiationdetectors may operate at any appropriate wavelength, and suchmodifications to the embodiments desirable to operate at any suchwavelength will be apparent to those skilled in the art. In someembodiments, the sensor 304 may be any of a disposable, reusable, and/orresposable sensor. Generally, for CCHD measurements, a sensor configuredfor use with an infant is desirable. In some embodiments, this mayinclude a finger, toe, or ear sensor. In an embodiment, the sensor 304may also be a wrist-type sensor configured to surround the wrist orankle of an infant. [0045]

The sensor 304 is coupled to the pulse oximeter 300 that processesand/or displays the sensor 304's output, on, for example, display 302.The sensor 304 may additionally be coupled to one or more monitors thatprocess and/or display the sensor 304's output. As described below inreference to FIG. 3B, the pulse oximeter 300 may include variouscomponents, such as a sensor front end, a signal processor, and/or adisplay, among other things.

The sensor 304 may be integrated with a monitor (such as the pulseoximeter 300), for example, into a handheld unit including the sensor304, a display and user controls. In other embodiments, the sensor 304may communicate with one or more processing devices. The communicationmay be through wire(s), cable(s), flex circuit(s), wirelesstechnologies, or other suitable analog or digital communicationmethodologies and devices to perform those methodologies. Many of theforegoing arrangements allow the sensor 304 to be attached to themeasurement site while the device (such as the pulse oximeter 300) isattached elsewhere on a patient, such as the patient's arm, or placed ata location near the patient, such as a bed, shelf or table. The sensor304 and/or pulse oximeter 300 may also provide outputs to a storagedevice or network interface.

FIG. 3B illustrates a simplified block diagram of a pulse oximeterconfigured to perform a CCHD screening process, as described above withreference to FIG. 3A. FIG. 3B includes the pulse oximeter 300, thesensor 304, and a communications link 322. The pulse oximeter 300includes a front-end interface 324, a signal processor 326, a userinterface processor 330, the display 302, a storage 334, a networkinterface 336, and an optional memory 328. In an embodiment, the signalprocessor 326 includes processing logic that determines measurements,for example, SpO₂ and/or PI. The signal processor 326 may be implementedusing one or more microprocessors or subprocessors (e.g., cores),digital signal processors, application specific integrated circuits(ASICs), field programmable gate arrays (FPGAs), combinations of thesame, and the like.

The signal processor 326 may provide various signals through thefront-end interface 324 and the communications link 322 that control theoperation of the sensor 304. For example, the signal processor 326 mayprovide an emitter control signal to the sensor 304. Additionally,measurement data may be transmitted from the sensor 304 to the signalprocessor 326. As also shown, the optional memory 328 may be included inthe front-end interface 324 and/or in the signal processor 326. Thisoptional memory 328 may serve as a buffer or storage location for thefront-end interface 324 and/or the signal processor 326, among otheruses.

The user interface processor 330 may provide an output, for example, onthe display 302, for presentation to a user of the pulse oximeter 300.The user interface processor 330 and/or the display 302 may beimplemented as a touch-screen display, an LCD display, an organic LEDdisplay, or the like. In addition, the user interface processor 330and/or display 302 may include a flip screen, a screen that can be movedfrom one side to another on the pulse oximeter 300, or may include anability to reorient its display indicia responsive to user input ordevice orientation. In alternative embodiments, the pulse oximeter 300may be provided without the display 302 and may simply provide an outputsignal to a separate display or system.

The storage 334 and the network interface 336 represent other optionaloutput connections that can be included in the pulse oximeter 300. Thestorage 334 may include any computer-readable medium, such as a memorydevice, hard disk storage, EEPROM, flash drive, or the like. Varioussoftware and/or firmware applications can be stored in the storage 334,which may be executed by the signal processor 326 and/or anotherprocessor of the pulse oximeter 300. The network interface 336 may be aserial bus port (RS-232/RS-485), a Universal Serial Bus (USB) port, anEthernet port, a wireless interface (e.g., WiFi such as any 802.1xinterface, including an internal wireless card), or other suitablecommunication device(s) that allows the pulse oximeter 300 tocommunicate and share data with other devices (such as, for example, aremote data processing center as described below in reference to FIG.5). The pulse oximeter 300 may also include various other components notshown, such as a microprocessor, graphics processor, and/or controllerto output a user interface, to control data communications, to computedata trending, and/or to perform other operations.

Although not shown in the depicted embodiment, the pulse oximeter 300may include various other components or may be configured in differentways. For example, the sensor 304 may measure additional advancedparameters. As described below, the pulse oximeter 300 may prompt theuser to take specific actions through the display 302 to, for example,accomplish the CCHD screening process.

FIG. 3C illustrates an example CCHD screening process according to anembodiment of the present disclosure. This CCHD screening process may beaccomplished with, for example, the pulse oximeter 300 of FIGS. 3A and3B. At box 362, sensor data is gathered at a first site. For example, atthis point the user/caregiver may be instructed to attach the pulseoximeter sensor (for example, the sensor 304) to the patient's righthand for a pre-ductal measurement. At box 364, sensor data is gatheredat a second site. For example, at this point the user/caregiver may beinstructed to attach the pulse oximeter sensor (for example, the sensor304) to the patient's foot or left hand for a post-ductal measurement.In each of boxes 362 and 364, the measurement data may be transmittedfrom the sensor 304, through the communications link 322 and front-endinterface 324, to the signal processor 326.

At box 366, the gathered pre- and post-ductal measurement data isprocessed by, for example, the signal processor 326. The gathered datais processed to provide both screening results (for example, the pre-and post-ductal SpO₂ measurements and the delta between the two), butalso to reduce errors in the measurements. As stated above, drawbacksarise when data from each time-displaced measurement (baseline andalternate, pre- and post-ductal) is not carefully selected. For example,normal infant SpO₂ values may drift up and down more than two percent(2%). If a baby holds its breath during onset of crying, values maydrift more than twenty percent (20%) in a very short time. If by chancethe baseline was taken at a coincidental peak in normal variation, andthe alternate was taken during crying or even at a valley or trough ofnormal variation, such error may impact a CCHD screening process, which,as shown in FIG. 2, may change the result based on a three percent (3%)differential between baseline and alternate.

As described above, FIG. 2 depicts the Centers for Disease Control andPrevention's (“CDC's”) recommended CCHD screening process 200. A screenis considered positive (see box 228) if (1) any oxygen saturationmeasurement is less than ninety percent (<90%) (in the initial screen orin repeat screens) (see boxes 206, 214, and 222); (2) the oxygensaturation measurement is less than ninety five percent (<95%) in theright hand and foot on three measures (see boxes 208, 216, and 224),each separated by one (1) hour (see boxes 204, 212, 220); or (3) agreater than three percent (>3%) absolute difference exists in oxygensaturation measurements between the right hand and foot on threemeasures (see boxes 208, 216, and 224), each separated by one (1) hour.Any screening that is greater than or equal to ninety five percent(≧95%) in the right hand or foot with a less than or equal to threepercent (≦3%) absolute difference in oxygen saturation measurementsbetween the right hand and foot is considered a negative screen andscreening would end (see boxes 210, 218, 226, and 230).

Referring back to FIG. 3C and box 366, in an embodiment, a process orprocesses executing on one or more signal processors (such as signalprocessor 326) seek to reduce errors introduced by, for example, thetime differential in measurements in the single sensor implementation ofCCHD screening processes. In an embodiment, confidence thresholds mayindicate when signal quality is sufficiently high to use measurementdata. Confidence information may also be used to weight data as it iscombined for comparisons. Confidence information may be assigned towindows of data and may be used to reduce an impact of a particularwindow on a measurement value or adjust the value itself. Suchconfidence information may be advantageously incorporated into a visualqueue, such as a number or a graphic, indicating a confidence in themeasurement or screening itself. An embodiment of a confidencemeasurement is displayed in FIG. 16. FIG. 16 shows an example plot 1600of a pre-ductal PI graph 1605 and a pre-ductal confidence graph 1610,each versus time (in seconds). The pre-ductal PI graph 1605 will bedescribed below. Pre-ductal confidence is indicated by pre-ductalconfidence graph 1610, which varies over time based on, for example,signal quality from the sensor 304 and/or PI measurements as shown inthe pre-ductal PI graph 1605. In an embodiment, a sufficiently lowconfidence level (and/or threshold) results in a measurement error, andno result is reported to the user/caregiver. For example, a confidencethreshold may be (on a scale of 0 to 1) 0.5, 0.6, 0.7, 0.8, 0.85, 0.9,0.95, 0.96, 0.97, 0.98, 0.99, and/or 1, among other possibilities.

Referring back to box 366 in FIG. 3C, additional processing may beaccomplished to ensure the measured data is reliable, and/or theuser/caregiver may be notified of possible problems with the gathereddata. Alternatively, the gathered data may be processed after it isgathered. For example, the sensor data at site one may be gathered andprocessed, followed by the gathering and processing of the sensor dataof site two.

In an embodiment, indications of motion may advantageously cause anaudio/visual message to be presented to a caregiver to calm the patientbefore measurements can be used. In an embodiment, a minimum wait timemay ensure that actual stabilization of the data occurs, such as forexample, about ten (10) to twenty (20) seconds or more may need to passafter an indication of cessation of motion in the patient.

In an embodiment, the features of the plethsmographic data or of theoxygen saturation data values can be analyzed to determine when to usemeasurement data. In the case of the plethsmographic data, determinationof how well the waveform fits a model may guide confidence measurementsor indicate signal noise. With saturation data, troughs and peaks, andtheir respective severities may be determined so that measurements foreach site are chosen during similar or the same waveform feature, suchas, for example, using measurements that correspond to peaks for eachsite. In an embodiment, the natural high and low cycles of oxygensaturation are used to correlate the measurements. For example, typicalpre- and post-ductal SpO₂ measurements are illustrated in FIG. 15. FIG.15 shows an example plot 1500, including a pre-ductal SpO₂ graph 1502and a post-ductal SpO₂ graph 1504, each versus time (in seconds). TheSpO₂ measurements vary cyclically over time. Thus, in order to comparemeasurements from two different sites taken at different times, thenatural cycles of variance in the SpO₂ are used to correlate themeasurement data. In the example of FIG. 15, a 60 second window of datais taken of both the pre- and post-ductal measurement. The data is timeadjusted so that the natural cycles of the SpO₂ measurements occur atroughly the same time. A window or timeframe, for example, a 30 secondwindow of time, is analyzed, indicated as 1510 and 1512, respectively,in FIG. 15. This window or timeframe is then used to determine the SpO₂delta 1514. As a result of correlating the pre- and post-ductal SpO₂measurements using the natural cycles, a more accurate delta can bedetermined.

Referring back to box 366 in FIG. 3C, in an embodiment, additionalprocessing may be performed and/or intermediate data may be accessed toassist in determining which measurements to select for screening deltas.For example, often sophisticated filters are used to smooth saturationmeasurements. In an embodiment, pre-filtered results may provide moreaccurate or immediate information on measurement selection. Similarly,ratio or other information may be used in addition to or in place offocusing on oxygen saturation values.

In an embodiment, phases in the respiration cycle may be accounted forto select measurement data. For example, measurement values maycorrespond to only data during, for example, the inspiration phase, orthe like. In an embodiment, respiration or pulse rates may qualify ordisqualify measurement data, based on, for example, rate stability orthe like.

Other parameter information may also be used. For example, perfusionindex (“PI”) information may provide indicators on when to selectmeasurement data. In an embodiment, PI may vary for reasons unrelated toCCHD and therefore can be used in certain implementations, such asranges that qualify or disqualify measurement data or the like. Forexample, the perfusion index may indicate that signal quality issufficiently high to use measurement data. A PI measurement is alsoillustrated in FIG. 16 as pre-ductal PI graph 1605. Although bothconfidence and PI have been illustrated with respect to a pre-ductalmeasurement in FIG. 16, it is to be understood that a similar PI andconfidence measure may also be determined for a post-ductal measurement.

In box 368 of FIG. 3C, the pulse oximeter 300 may optionally communicatewith a remote data processing center, through, for example, the networkinterface 336. As described below in reference to FIG. 5, currentmeasurement data may be transmitted to the remote data processingcenter, and/or previous measurement data may be accessed from the remotedata processing center, among other things. Thus, the results ofmultiple measurements may be stored, retrieved, and/or compared as partof the CCHD screening process. Alternatively, measurement data may bestored at the pulse oximeter 300. In an embodiment, the data processingof box 366 takes place at the remote data processing center.

In box 370, the results of the CCHD screening are reported to thecaregiver/patient/user. This may be accomplished, for example, bydisplaying the results on the display 302 as a number, color, and/orother symbol, and/or aurally in the form of, for example, an alarm.

An artisan will recognize from the disclosure herein a wide variety ofindicators or combinations of indicators for determining when to selectmeasurement data for use in CCHD screening processes. For example,segments or whole windows of data for the various parameters andindicators discussed in the foregoing may be combined to provideadditional insight into measurement selection. Moreover, any orcombinations of the foregoing may be used to adjust a particularmeasurement instead of seeking a different measurement.

FIG. 4 illustrates an embodiment of the CCHD screening systemincorporating dual (or stereo) sensors. FIG. 4 includes a pulse oximeter400, a signal processing device 406, a first sensor 408, and a secondsensor 409. Further, the pulse oximeter 400 includes a display 402, acommunication port 403, and a portable oximeter 404. Such a pulseoximeter is commercially available from Masimo Corporation of Irvine,Calif. Other CCHD systems may employ more than two sensors. In anembodiment, the pulse oximeter 400 includes a USB or other communicationport 403 that connects to the signal processing device 406. In thisembodiment, each of the dual sensors (first sensor 408 and second sensor409) connects to the signal processing device 406. Either of the firstsensor 408 or the second sensor 409, or both the first sensor 408 andthe second sensor 409, may comprise any combination of disposable,reusable, and/or resposable sensors. As described above, the firstsensor 408 and/or the second sensor 409 may be configured for use withan infant. Additionally, the two sensors are not required to be of thesame type, but may be any combination of suitable sensors. For example,in some embodiments, the first sensor 408 and/or the second sensor 409may include finger, toe, or ear sensors, or any combination of finger,toe, or ear sensors. In another example, the first sensor 408 and/or thesecond sensor 409 may be a wrist-type sensor configured to surround thewrist or ankle of an infant. The signal processing device 406 providesstereo processing of sensor signals, such as those disclosed in the '065patent. In an embodiment, such processing may include separate oximetercalculators logically similar to having two independent oximeters, onefor each sensor. The pulse oximeter 400 may include components similarto those of the pulse oximeter 300 of FIG. 3B. Specifically, the pulseoximeter 400 may include a signal processor, among other things.Processing of sensor data may take place in the pulse oximeter 400and/or the signal processing device 406.

In this stereo embodiment of two (2) or more sensors, while there maynot necessarily be time differentials between measurements, the datafrom each sensor may be of varying quality. Thus, many of the sameprocedures disclosed in the foregoing will apply. For example, at aparticular time, the data from the baseline sensor may be clean with ahigh confidence while the data from the alternate sensor may have lowquality from motion artifact, such as, for example, an infant kickingbut not moving their right hand. Thus, the signal processing device 406may use the foregoing processes to select measurement values from eachsensor at different times. In such cases, determining which measurementsshould be used involves determinations similar to those used in thesingle sensor implementation. Alternatively, the signal processingdevice 406 may wait and select a time when both sensors produce usablemeasurement data, similar data conditions, or the like.

In an embodiment, the signal processing device 406 determinesmeasurements for each of first sensor 408 and second sensor 409, andforwards measurement values to the pulse oximeter 400. The monitor 400advantageously includes CCHD screening modules that guide a caregiverthrough the screening process. In other embodiments, the signalprocessing device 406 executes the screening and sends flags or messagesto the display 402 and/or the portable oximeter 404 directing thedisplay 402 and/or the portable oximeter 404 to display caregiverinstructions and/or output results.

Although disclosed as the processing device 406 separate from the pulseoximeter 400, an artisan will recognize from the disclosure herein thatthe processing of the signal processing device 406 may be incorporatedinto the pulse oximeter 400 and/or the portable oximeter 404.

FIG. 5 illustrates a data diagram of a data sharing system, according toan embodiment of present disclosure. FIG. 5 includes a patient monitor502, a remote data processing center 504, and a network 506. In anembodiment, the patient monitor 502 may include, for example, either thepulse oximeter 300 of FIG. 3A or the pulse oximeter 400 of FIG. 4. In anembodiment, the patient monitor 502 and the network 506 may communicatewith one another, and may be located in a hospital, while both thepatient monitor 502 and the network 506 may advantageously communicatewith the remote data processing center 504. The network 506 may include,for example, Masimo's Patient SafetyNet System, a hospital patient datasystem, and/or any other wired or wirelessly connected system. Anartisan will recognize that communications among any of the patientmonitor 502, the remote data processing center 504, and the network 506may be through any appropriate wired and/or wireless data transmission,and may use any suitable communications protocol. For example,communication may be serial or parallel, through Universal Serial Bus(USB) (wired or wireless), Ethernet, Bluetooth, Near FieldCommunications (NFC), radio frequency (RF), infrared, and/or WiFi (suchas any 802.1x interface), among others as is known in the art.

In an embodiment, the remote data processing center 504 may store, forexample, Patient ID's, device information (such as, for example, patientmonitor 502 device information), sensor information, measurement data,screening data, and/or screening determinations for comparisons withlater screening events. For example, the CCHD screening process of FIG.2 includes multiple repeat screens. In this example, previous screeningdata for a particular patient, among other things, may be requested bythe patient monitor 502, when for example, a new screening is performed.Thus, the data from the two screening may be compared or used in someother way. Such communication may advantageously be wirelessly directedfrom the patient monitor 502 to the remote data processing center 504,or through one or more intermediary networks (such as the network 506).For example, the patient monitor 502 may include wireless communicationto a hospital or other network which eventually communicates with theremote data processing center 504.

In an embodiment, the pulse oximeter 300 may communicate with network506 (or other host digital network or system) to store or uploadmeasurement data associated with a unique identifier to remote dataprocessing center 504. The network 506 may include multiple networks orsystems. The pulse oximeter 300 may access previously storedinformation, such as, for example, earlier screening data stored at theremote data processing center 504 of a remote network, to complete orincrement the CCHD screening process. In an embodiment, a first networkmay be an institutional network such as a hospital data system, acellular or other data system, or the like, wirelessly communicatingwith the pulse oximeter 300 or monitor. The system or systems eventuallyallow communication to a remote data processing center 504 or otherprocessing center that stores the measurement information in a mannerthat provides for retrieval and appropriate association with newlyacquired data.

As will be described in detail below, FIGS. 6-9, 10A-B, 11A-B, 12A-C,13A-C, and 14A-D illustrate example screen shots and/or displays of apulse oximeter monitor (such as the pulse oximeter 300 of FIG. 3A or thepulse oximeter 400 of FIG. 4) and/or other CCHD measurement deviceconfigured for measuring CCHD, according to embodiments of the presentdisclosure.

FIG. 6 illustrates a screen shot 600 of a pulse oximeter monitorconfigured for measuring CCHD. The screen shot 600 includes a firstscreen 602, second screen 604, and third screen 606 for measuring CCHD.These three screens correlate to the three separate measurementrecommendations for measuring CCHD, as described in reference to FIG. 2.A touch screen can be provided in the pulse oximeter monitor so that acaregiver need only touch each measurement (for example, first screen602, second screen 604, and third screen 606) in succession to begin thethree different measurement processes.

FIG. 7 illustrates various spot check settings that are available on thepulse oximeter monitor and/or CCHD measurement device of the presentdisclosure. A SpO₂ delta 702 allows a caregiver to dictate a specificdifference in SpO₂ between measurement sites that will indicate a CCHDproblem. The value can range between 1 and 10 with a default value of 3.The low SpO₂ threshold 704 indicates a minimal passing SpO₂ value for atest result. The value can range between 85-100 with a default value of95. The all mute 706 mutes all noise from the pulse oximeter monitorand/or CCHD measurement device. The low PI threshold 708 indicates aminimum PI measurement value that may still indicate a valid testresult. This value can range between 0.1 and 1 with a default value of0.7.

FIG. 8 illustrates a display of a first test results page 800. The firsttest results page 800 includes a first test results indication 801. Inthe embodiment of first test results page 800, a positive result wasobtained, but it was at a saturation value of less than 95%. The firsttest results page 800 also includes the time of the test 802, thepre-ductal results 804 and post-ductal results 810, including therespective SpO₂ values 806, 812 and PI values 808 and 814, as well asthe delta SpO₂ 816 illustrating the delta SpO₂ value 818. The first testresults page 800 also includes a next step indication 820. For example,in the embodiment of FIG. 8, the next step may indicate that a secondscreen test is to be performed in an hour. Alternatively, the next stepmay indicate that no further testing is required (in the event of, forexample, a negative screen).

FIG. 9 illustrates another example of a first test results page 900. Thetest results page has similar features corresponding to that of FIG. 8shown in an alternative format. The first test results page 900 includesa first test results indication 901. In the embodiment of first testresults page 900, a positive result was obtained. The first test resultspage 900 also includes the time of the test 902, the pre-ductal results904 and post-ductal results 910, including the respective SpO₂ values906, 912 and PI values 908 and 914, as well as the delta SpO₂ 916illustrating the delta SpO₂ value 918. The first test results page 900also includes a next step indication 920.

FIGS. 10A and 10B illustrate additional alternative embodiments ofsettings available for the CCHD monitor of the present disclosure.Referring to FIG. 10A, screen 1000 includes settings which indicate thedifference in SpO₂ readings (SpO₂ difference 1002) between sites toindicate a CCHD problem. The screen settings also include passing SpO₂low limit 1004, positive result SpO₂ threshold 1006, and enable PI 1008.Referring to FIG. 10B, additional settings on screen 1020 includepositive result SpO₂ threshold 1022, enable PI 1024, positive result PIthreshold 1026, and settings defaults 1028. The settings defaults caninclude different protocols for measuring CCHD including the KemperProtocol.

FIG. 11A illustrates additional advanced settings in screen 1100,including a time window 1102, a correlation window 1104, a minimumconfidence 1106, and minimum PI 1108. In FIG. 11B other settings areillustrated in screen 1120, including minimum confidence 1122, minimumPI 1124, minimum correlation 1126, and mean trim 1128.

Once all of the settings are configured, the CCHD screening device ofthe present disclosure provides step by step instructions for performinga CCHD test protocol. FIGS. 12A-C, 13A-C, and 14A-D illustrateinstructions provided for the single sensor CCHD monitor of the presentdisclosure. FIGS. 12A-C illustrate an embodiment of various protocolstep-by-step instructions. For the pre-ductal measurement, instructionscreen 1200 instructs a caregiver to place the sensor on the right handand press a button on the screen to move to the next instruction screen1220. Instruction screen 1220 indicates that a measurement is takingplace. If an error occurs in the measurement, an error screen 1240 isdisplayed. In an embodiment, the CCHD screening system (including, forexample, pulse oximeter 300 or pulse oximeter 400) controls and tracksthe implementation of the screening process, including instructions tocaregivers on next steps, as described. Additional examples ofinstruction may include “Attach Sensor to Right Hand,” “Attach Sensor toAlternate Site,” “Attach Sensor to Right Foot,” “Attach Sensor to LeftFoot,” “Calm Patient,” “Adjust Sensor Positioning,” or the like.

Once the pre-ductal measurement is obtained, the instructions move on tothe instruction screens of FIGS. 13A-C. Instruction screen 1300, labeledas step 3, instructs the caregiver to place the sensor on the eitherfoot of the patient and press a button to continue to instruction screen1320. In instruction screen 1320, labeled as step 4, the post-ductalmeasurement is obtained. If an error occurs in the post-ductalmeasurement, an error screen 1340 is presented to the user.

The instructions continue with FIGS. 14A-D. Once the post-ductalmeasurement is obtained, results screen 1400, labeled as step 5, isdisplayed. The results screen 1400 provides the pre- and post-ductalscreening results, as well as the difference in SpO₂. The results screen1400 illustrates an embodiment in which a passing test was obtained andinstructions that the test was passed are provided on the screen at1405. Alternatively, if a potential problem was found, as illustrated inresults screen 1420 of FIG. 14B, then an instruction is provided at 1425instructing the care giver to perform a second test in one hour. If asecond screening indicates a failing test, as illustrated in resultsscreen 1440 of FIG. 14C, then an instruction is provided to perform athird screen testing in one hour at 1445. If the results of the thirdtest also indicate a problem, for example in screen 1460 of FIG. 14D,then an instruction is provided to refer the newborn for further medicalevaluation at 1465. As described above, the CCHD screening system mayinclude a quality indicator providing information on the confidence inthe screening measurements. A quality measure may be included for eachmeasurement, for the entire screen, or the like. For example, thedisplay may indicate “Positive Screen, 72% Confidence.” In anembodiment, a minimum confidence threshold may be used to instruct acaregiver to repeat the measurements and/or restart the screeningprocess. Moreover, the oximeter may produce an audio/visual alarmindicating time for a repeat screen, may accept patient informationincluding a patient identifier, and the like.

Although the foregoing has been described in terms of certain preferredembodiments, other embodiments will be apparent to those of ordinaryskill in the art from the disclosure herein. For example, other CCHDscreening methodologies may take advantage of the processes for matchingmeasurements disclosed herein. Moreover, data conditions from one screenmay influence when measurements are chosen for subsequent screens. Forexample, if choosing according to peaks in the SpO₂ values wasimplemented to match measurement conditions in one screen, the same maybe used or implemented in subsequent screens. Accordingly, the presentdisclosure is not intended to be limited by the reaction of thepreferred embodiments, but is to be defined by reference to the appendedclaims.

In addition to the foregoing, all publications, patents, and patentapplications mentioned in this specification are herein incorporated byreference to the same extent as if each individual publication, patent,or patent application was specifically and individually indicated to beincorporated by reference.

Moreover, the oximeters discussed in the foregoing may include many orall of the features of basic pulse oximeters that determine measurementsfor blood oxygen saturation (“SpO₂”), pulse rate (“PR”) andplethysmographic information, to read-through-motion oximeters, toco-oximeters that determine measurements of many constituents ofcirculating blood. For example, Masimo Corporation of Irvine Calif.(“Masimo”) manufactures pulse oximetry systems including Masimo SET® lownoise optical sensors and read through motion pulse oximetry monitorsfor measuring SpO₂, PR, perfusion index (“PI”) and others. Masimosensors include any of LNOP®, LNCS®, SofTouch™ and Blue™ adhesive orreusable sensors. Masimo oximetry monitors include any of Rad-8®,Rad-5®, Rad-5v® or SatShare® monitors.

Also, many innovations improving the measurement of blood constituentsare described in at least U.S. Pat. Nos. 6,770,028; 6,658,276;6,157,850; 6,002,952; 5,769,785 and 5,758,644, and are incorporated byreference herein. Corresponding low noise optical sensors are disclosedin at least U.S. Pat. Nos. 6,985,764; 6,813,511; 6,792,300; 6,256,523;6,088,607; 5,782,757 and 5,638,818, and are incorporated by referenceherein.

Masimo also manufactures more advanced co-oximeters including MasimoRainbow® SET, which provides measurements in addition to SpO₂, such astotal hemoglobin (SpHb™), oxygen content (SpCO™), methemoglobin(SpMet®), carboxyhemoglobin (SpCO®) and PVI®. Advanced blood parametersensors include Masimo Rainbow® adhesive, ReSposable™ and reusablesensors. Masimo's advanced blood parameter monitors include MasimoRadical-7™, Rad-87™, and Rad-57™ monitors as well as Pronto and Pronto-7spot check monitors.

Innovations relating to these more advanced blood parameter measurementsystems are described in at least U.S. Pat. Nos. 7,647,083; 7,729,733;U.S. Pat. Pub. Nos. 2006/0211925; and 2006/0238358, incorporated byreference herein.

Such advanced pulse oximeters, low noise sensors and advanced bloodparameter systems have gained rapid acceptance in a wide variety ofmedical applications, including surgical wards, intensive care andneonatal units, general wards, home care, physical training, andvirtually all types of monitoring scenarios.

Thus, by employing the embodiments of the CCHD screening processes andsystems disclosed herein, CCHD, particularly PDA, may be more accuratelydetected and diagnosed. Specifically, false positives may be reduced,variances in SpO₂ may be detected and filtered, caregivers may be moreproperly directed, and/or measurement confidence may be evaluated, amongother advantages.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orstates. Thus, such conditional language is not generally intended toimply that features, elements and/or states are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or states are included or are to beperformed in any particular embodiment.

While certain embodiments of the inventions disclosed herein have beendescribed, these embodiments have been presented by way of example only,and are not intended to limit the scope of the inventions disclosedherein. Indeed, the novel methods and systems described herein can beembodied in a variety of other forms; furthermore, various omissions,substitutions and changes in the form of the methods and systemsdescribed herein can be made without departing from the spirit of theinventions disclosed herein. The claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of certain of the inventions disclosed herein.

1. (canceled)
 2. A method of determining a likelihood of a criticalcongenital heart defect using a pulse oximeter, the method comprising:displaying, on a display of a pulse oximeter, instructions to acaregiver to position a noninvasive sensor at a first measurement siteon a patient predetermined to be substantially indicative of apre-ductal blood oxygenation level and not substantially indicative of apost-ductal blood oxygenation level, wherein the noninvasive sensor isconfigured to output signals responsive to attenuation of light atmeasurement sites on the patient to the pulse oximeter, wherein thefirst measurement site is on a first limb of the patient; displaying, onthe display of the pulse oximeter, an indication to the caregiver of asuccess or failure of obtaining a measure of pre-ductal bloodoxygenation level at the first measurement site; displaying, on thedisplay of the pulse oximeter, instructions to the caregiver to positionthe noninvasive sensor at a second measurement site on the patientpredetermined to be substantially indicative of a post-ductal bloodoxygenation level and not substantially indicative of a pre-ductal bloodoxygenation level, wherein the second measurement site is on a secondlimb of the patient, and wherein the second limb of the patient isdifferent from the first limb of the patient; displaying, on the displayof the pulse oximeter, an indication to the caregiver of a success orfailure of obtaining a measure of post-ductal blood oxygenation level atthe second measurement site; processing, by one or more hardwareprocessors of the pulse oximeter, the pre-ductal blood oxygenation leveland the post-ductal oxygenation level to determine a likelihood that thepatient has a critical congenital heart defect; and displaying, on thedisplay of the pulse oximeter, an indication to the caregiver of thelikelihood that the patient has the critical congenital heart defect. 3.The method of claim 2 further comprising: displaying, on the display ofthe pulse oximeter, instructions to the caregiver to proceed with anadditional screening for the critical congenital heart defect after aperiod of time.
 4. The method of claim 2, wherein displaying theindication of the likelihood that the patient has the criticalcongenital heart defect comprises: displaying, on the display of thepulse oximeter, an indication of a difference between the measure ofpre-ductal blood oxygenation level and the measure of post-ductal bloodoxygenation level
 5. The method of claim 4, wherein displaying theindication of the likelihood that the patient has the criticalcongenital heart defect further comprises: displaying, on the display ofthe pulse oximeter, an indication of the measure of pre-ductal bloodoxygenation level and the measure of post-ductal blood oxygenationlevel.
 6. The method of claim 5, wherein displaying the indication ofthe likelihood that the patient has the critical congenital heart defectfurther comprises: displaying, on the display of the pulse oximeter,respective measures of perfusion index associated with each of themeasure of pre-ductal blood oxygenation level and the measure ofpost-ductal blood oxygenation level.
 7. The method of claim 6, whereindisplaying the indication of the likelihood that the patient has thecritical congenital heart defect further comprises: displaying, on thedisplay of the pulse oximeter, an indication of a confidence in the ascreening associated with the likelihood that the patient has thecritical congenital heart defect.
 8. The method of claim 2 furthercomprising: displaying, on the display of the pulse oximeter, anindication of a progress of obtaining the measure of pre-ductal bloodoxygenation level at the first measurement site.
 9. The method of claim2 further comprising: displaying, on the display of the pulse oximeter,an indication of a progress of obtaining the measure of post-ductalblood oxygenation level at the second measurement site.
 10. The methodof claim 2, wherein the first measurement site comprises a right hand ofthe patient.
 11. The method of claim 10, wherein the second measurementsite comprises at least one of a foot or left hand of the patient. 12.The method of claim 2, wherein processing, by the one or more hardwareprocessors of the pulse oximeter, the pre-ductal blood oxygenation leveland the post-ductal oxygenation level to determine the likelihood thatthe patient has a critical congenital heart defect comprises: receiving,during a first duration of time, the output signals to obtain a firstwaveform responsive to a pre-ductal oxygen saturation of the patient,the first duration of time corresponding to when the noninvasive sensoris positioned at the first measurement site; receiving, during a secondduration of time, the output signals to obtain a second waveformresponsive to a post-ductal oxygen saturation of the patient, the secondduration of time corresponding to when the noninvasive sensor ispositioned at the second measurement site; electronically determining,by the one or more hardware processors, one or more waveform features inthe first waveform responsive to the pre-ductal oxygen saturation;electronically determining, by the one or more hardware processors, oneor more of the one or more waveform features in the second waveformresponsive to the post-ductal oxygen saturation; electronicallytime-wise aligning, by the one or more hardware processors, one or moreof the one or more waveform features from the first waveform with one ormore of the one or more waveform features from the second waveform;electronically determining, by the one or more hardware processors, apre-ductal value of the first waveform at a first time; andelectronically determining, by the one or more hardware processors, apost-ductal value of the second waveform at the first time taking intoaccount the time-wise aligning, wherein displaying the indication of thelikelihood that the patient has the critical congenital heart defectcomprises: in response to determining the pre-ductal value and thepost-ductal value differ by a predetermined threshold, outputtingdisplay indicia to the display indicating a likelihood that the patienthas the critical congenital heart defect.
 13. The method of claim 12,wherein said first time comprises a third duration of time, and whereindetermining said pre-ductal value and said post-ductal value differ bythe predetermined threshold comprises: calculating an average differencebetween said pre-ductal value and said post-ductal value over the thirdduration of time.
 14. The method of claim 13, wherein said firstduration of time and said second duration of time each comprise at leastsixty seconds.
 15. The method of claim 14, wherein said third durationof time comprises at least thirty seconds.
 16. The method of claim 12,wherein said one or more waveform features from said first waveformcomprise at least one of: a trough, a peak, a natural high cycle ofoxygen saturation, a natural low cycle of oxygen saturation, or acyclical variation.
 17. The method of claim 12, wherein processing, bythe one or more hardware processors of the pulse oximeter, thepre-ductal blood oxygenation level and the post-ductal oxygenation levelto determine the likelihood that the patient has a critical congenitalheart defect further comprises: discarding a waveform when a quality ofsaid output signals is outside of a pre-determined range.
 18. The methodof claim 12, wherein processing, by the one or more hardware processorsof the pulse oximeter, the pre-ductal blood oxygenation level and thepost-ductal oxygenation level to determine the likelihood that thepatient has a critical congenital heart defect further comprises:receiving said signal outputs to obtain a third waveform responsive to ablood perfusion level of the patient, wherein a waveform is discardedwhen the blood perfusion level associated with the waveform is outsideof a pre-determined range.
 19. A pulse oximetry based system configuredto determine a likelihood of a critical congenital heart defect, thesystem comprising: a noninvasive sensor configured to output signalsresponsive to an attenuation of light at measurement sites on a patient;and a pulse oximeter in communication with the noninvasive sensor todrive light sources of said noninvasive sensor and to receive saidoutput signals, said pulse oximeter including one or more hardwareprocessors configured to: display, on a display of the pulse oximeter,instructions to a caregiver to position the noninvasive sensor at afirst measurement site on a patient predetermined to be substantiallyindicative of a pre-ductal blood oxygenation level and not substantiallyindicative of a post-ductal blood oxygenation level; display, on thedisplay of the pulse oximeter, an indication to the caregiver of asuccess or failure of obtaining a measure of pre-ductal bloodoxygenation level at the first measurement site; display, on the displayof the pulse oximeter, instructions to the caregiver to position thenoninvasive sensor at a second measurement site on the patientpredetermined to be substantially indicative of a post-ductal bloodoxygenation level and not substantially indicative of a pre-ductal bloodoxygenation level, wherein the second measurement site is on a secondlimb of the patient, and wherein the second limb of the patient isdifferent from the first limb of the patient; display, on the display ofthe pulse oximeter, an indication to the caregiver of a success orfailure of obtaining a measure of post-ductal blood oxygenation level atthe second measurement site; process, by the one or more hardwareprocessors of the pulse oximeter, the pre-ductal blood oxygenation leveland the post-ductal oxygenation level to determine a likelihood that thepatient has a critical congenital heart defect; and display, on thedisplay of the pulse oximeter, an indication to the caregiver of thelikelihood that the patient has the critical congenital heart defect.20. The system of claim 19, wherein processing, by the one or morehardware processors of the pulse oximeter, the pre-ductal bloodoxygenation level and the post-ductal oxygenation level to determine thelikelihood that the patient has a critical congenital heart defectcomprises: receiving, during a first duration of time, the outputsignals to obtain a first waveform responsive to a pre-ductal oxygensaturation of the patient, the first duration of time corresponding towhen the noninvasive sensor is positioned at the first measurement site;receiving, during a second duration of time, the output signals toobtain a second waveform responsive to a post-ductal oxygen saturationof the patient, the second duration of time corresponding to when thenoninvasive sensor is positioned at the second measurement site;electronically determining, by the one or more hardware processors, oneor more waveform features in the first waveform responsive to thepre-ductal oxygen saturation; electronically determining, by the one ormore hardware processors, one or more of the one or more waveformfeatures in the second waveform responsive to the post-ductal oxygensaturation; electronically time-wise aligning, by the one or morehardware processors, one or more of the one or more waveform featuresfrom the first waveform with one or more of the one or more waveformfeatures from the second waveform; electronically determining, by theone or more hardware processors, a pre-ductal value of the firstwaveform at a first time; and electronically determining, by the one ormore hardware processors, a post-ductal value of the second waveform atthe first time taking into account the time-wise aligning, whereindisplaying the indication of the likelihood that the patient has thecritical congenital heart defect comprises: in response to determiningthe pre-ductal value and the post-ductal value differ by a predeterminedthreshold, outputting display indicia to the display indicating alikelihood that the patient has the critical congenital heart defect.